1. Field of the Invention
This invention relates to connector cable systems, and more particularly to a unified connector and receptacle therefor, where the unified connector is formed by a joining together of two connectors, each from a separate cable.
2. Description of the Prior Art
Harnesses made of electrical conductors, optical fibers or a hybrid thereof, are used in order to connect a source device to one or more remote devices. This may be for purposes of data transmission or power transmission or a combination thereof. An example of a simple harness is the case of a cable connecting a source of power, such as a battery, to a switch and then to an actuator, such as a power window motor in an automobile. In such a simple circuit it is very easy to design a harness using a cable having the appropriate connectors. This matter becomes seriously complicated, however, in situations involving a number of end devices, where each end device must be serially linked under independent control to a source device. Frequently, this is accomplished through use of a multiplexing system. An example of such a circuit topology is shown schematically in FIG. 1, where an automobile 10 has a number of end devices in the form of a power window actuator 12 and an electric door lock actuator 14 located in each of its four doors 16. It will be seen from the figure that a harness 17 is in the form of a closed loop composed of four cable segments 18 which are serially linked by connections to multiplexing modules 19. The harness 17 is composed of a plurality of cable segments 18 because it is extremely difficult to install it as a single piece unit in the automobile.
Because of connector multiplicity, complexity, and cost, harness installations that incorporate a number of individual cable segments are not desirable. However, as explained above, frequently it is not practicable to install a single piece harness in a particular installation. Accordingly, what is needed is a simple and inexpensive connector that will link these cable segments into what is effectively a single piece harness.
In the prior art, various connector systems are known. U.S. Pat. No. 4,596,436 to Kraemer et al, discloses an electrical connector housing having located therein connector modules 28, 30, and 32. Each of the connector modules remain separated in space, and each is intended to be mated separately with a respective connector from outside the housing. U.S. Pat. No. 4,073,564 to Davis, Jr., discloses a christmas tree lighting string which has a two part plug that can be separated to allow the string to be stretched out linearly. This plug configuration allows easy and untangled storage of the string, as well as a convenient means to untangle the string during use. This device is structured to operate with only a single lighting string.
In my co-pending U.S. patent application Ser. No. 946,308, now U.S. Pat. No. 4,767,168 filed Dec. 24, 1986, entitled "A Hybrid Connector Cable System," hereby incorporated by reference, a hybrid optical and electrical connector is described.
As can be seen from FIG. 2, a hybrid cable 22 is provided having two end connectors 24 and 26. The hybrid cable 22 embodies at least one optical conductor fiber 28 and at least one electrical conductor 32. The hybrid cable 22 may also have a second optical conductor fiber 30 and a second electrical conductor 34 which may function as a ground wire or the conductor for a regulated voltage, as desired.
The connectors 24 and 26 are preferably made from a structural plastic material injection molded onto the ends of the hybrid cable 22. The input connector 24 has a plurality of connector pins 36 provided at the end thereof. The connector pins 36 may be disposed along two or more lines, or may be disposed in a circle or any pattern as desired for a given application. The two electrical leads of a photodetector 38 for converting a light signal to an electrical signal, such as a photodiode or phototransistor, are electrically connected to a first pair of connector pins 36, while the two electrical leads of a light source 40 for converting an electrical signal to a light signal, such as a light emitting or laser diode or any other device for generating a light signal, are electrically connected to a second pair of connector pins 36. Each of the electrical conductors 32 and 34 are connected directly to a separate connector pin 36.
The leads from the photodetector 38 and the light source 40 as well as the two electrical conductors 32 and 34 are electrically connected to the connector pins 36 using any of the conventional methods known in the art. They may be crimped, soldered, or welded to make a mechanically strong electrical connection.
The photodetector 38 and the light source 40 are mounted on a component board 42 to prevent their displacement during the injection molding of the connector 24. The component board 42 also has provisions for retaining wire clamps 44 for positioning the electrical or metal conductors 32 and 34 relative to their respective connector pins 36, and fiber clamps 46 for positioning the optical conductor fibers 28 and 30 relative to the photodetector 38 and the light source 40, respectively.
The structure of the output connector 26 attached to the other end of the hybrid cable 22 is identical to the structure of the input connector 24 discussed above, except at this end of the hybrid cable 22, a photodetector 48 is optically connected to the optical conductor fiber 30 and a light source 50 is optically connected to the optical conductor fiber 28. In this manner, each optical conductor fiber has a light source disposed at one end and a photodetector disposed at the other end.
The structure of the photodetector 38 is shown in FIG. 3. The photodetector 38 has a solid state photodetector element 52, such as a photodiode or phototransistor, the electrical leads of which are connected to a pair of pins 54 and 56 protruding from an insulator base 58. The photodetector element 52 is encapsulated in a plastic housing 60 which is transparent to the received light signal. The housing 60 also supports the photodetector element 52 relative to the insulator base 58. An aperture 62 is provided in the plastic housing 60 directly in line with the sensitive area of the photodetector element 52. The aperture 62 receives and positions the end of the optical conductor fiber 28 adjacent to the photosensitive area of the photodetector element 52. The optical conductor fiber 28 may be glued or cemented to the aperture 62 to hold it in place during the extrusion molding of the input connector 24.
Preferably, a thin layer of the transparent plastic used in fabrication of the plastic housing 60 is left at the bottom of the aperture 62 to cover the photosensitive area of the photodetector element 52 to protect it from abrasion by the end of the optical conductor fiber 28.
The structure of the light source, such as the light emitting or laser diodes 40 or 50, is similar to the structure of the photodetector 38 shown in FIG. 3 except that the photodetector element 52 is replaced by a light emitting element. The light source 40 generates a light signal which is transmitted by the optical conductor fiber 30 to the output connector 26 which is received by the photodetector 48. In a like manner, the light source 50 generates a light signal which is transmitted by the optical conductor fiber 28 to the input connector 24 where it is received by the photodetector 38. The structure of the photodetector 48 in the output connector 26 is the same as the photodetector 38 illustrated in FIG. 3.
It, therefore, remains a problem in the prior art to devise a simple, effective, and reliable connector which can combine separate cables, having either electrical conductors, optical conductor fibers, or a hybrid thereof, into what is effectively a single piece harness.